In recent years, harmony with global environment or reduction of environmental burdens is becoming a major issue in the industry. Therefore, the development of environmentally friendly products or technologies is accelerating. This movement is seen in a technical field of the present invention. In particular, an organotin catalyst, which is widely used as a catalyst for a polythiourethane resin, has been concerned because it is harmful to humans as it is highly toxic, may become the endocrine disruptor, etc. Consequently, regulation on the use of organotin compounds has been strengthened primarily in developed countries. In a spectacle lens industry employing polythiourethane resins, development of an alternative catalyst to the organotin catalyst has been required. As the tin-free non-metallic catalyst which a general thermosetting resin can be obtained, amine compounds, amine carboxylate, phosphine and the like are known (Patent Documents 1, 2, 3, 4 and 5).
[Patent Document 1] Japanese Laid-open patent publication No. H03-084021
[Patent Document 2] Japanese Laid-open patent publication No. S63-077918
[Patent Document 3] Japanese Laid-open patent publication No. S62-016484
[Patent Document 4] Japanese Laid-open patent publication No. H09-077850
[Patent Document 5] Japanese Laid-open patent publication No. 2000-256571